Muffler device for telephones



Nov. 3, 1925. 1,559,581

K. J. NASH MUFFLER DEVICE FOR TELEPHONES Filed June 1. 1925 Patented Nov. 3, 1925.

UNITED STATES PATENT OFFICE.

KARL J. NASH, OF KANSAS CITY, MISSOURI.

MUFFLER DEVICE FOR TELEPHON'ES.

Application filed June 1, 1925 Serial No. 34,013.

To all whom it may comem:

Be it known that I, KARL J. NAsH, a citizen of the United States, residing at Kansas City, in the county of Jackson and State of Missouri, have. invented a new and useful Muflicr Device for Telephones, of which the following is a specification.

My invention relates to mufiier devices for telephones, and the object of the invention is to provide an inexpensive, portable, mufiier attachment for telephone transmitters having facility to quiet noises and sounds incident to talking into the transmitter to render telephonic talks inaudible to persons in the vicinity of the telephone and, thereby, making possible private and secret telephony without the aid of isolated sound proof booths.

I attain these objects and other advantages by means of the structure and combination of parts illustrated in the accompanying drawing in whichFigure 1 is a vertical section of the device, showing the same applied to a telephone transmitter. Figure 2 is an inner end View of the band for supporting the device, and showing the sound absorbing device therein, a part of my invention. Figure 3 is an outer end view of the supporting band, and showing the rubber cushion therein for receiving the telephone transmitter case and, Figure 4, is a cross section of the spool shaped inner tube, a part of my invention.

Similar numerals of reference refer to corresponding parts throughout the several views.

Referring to the drawingsthe numeral 1 designates a telephone transmitter and 2 the mouth piece associated therewith. -The device comprising the invention consist-s of a circular tube portion 3 and having integral with its front end an annular inwardly turned flange 4 having a mouth piece 5 secured to its inner edge. The tube 3 form a cylindrical casing and in which is slidably lodged a spool shaped cylindrical hollow body 6, provided at its opposite ends with vertical annular flanges 7 which slidably bear on the inner side of the wall of the casing and, thereby, form with the walls of the casing and the body an annular chamher 8 which encircles the hollow body for a purpose that will hereinafter be fully explained. The wall of the body 6 is provided with oppositely located longitudinally extending apertures 9 and through which there is communication between the body 6 and the chamber 8. The one end of the cut away portions of the wall of the body, at the apertures 9, are formed outwardly a little distance at a tangent to form deflector portions 10 adapted to deflect sound waves entering the aperture into the chamber 8 in the same direction. A band supporting member 11 adapted to frictionally receive the rearward end of the casing and receive the transmitter case in opposed relation is provided at a point intermediate of its W dth, with an inwardly extending concentric flange 12. A plurality of set screws 13 are operatively mounted in the band 11 and outwardly of the flange 12. A washer 14, made of suitable flexible and resilient material, preferably, wool felt, is disposed in the inner end of the band 11 and against the flange 12, the washer being, preferably, wider than the width of the flange 12, as shown in Figures 1 and 3, so that the inner margin of the washer shall encircle the neck of the mouth piece of the transmitter. A rubber washer 15 having a peripheral flange 16 extending outwardly of the band is lodged in the band and against the outer side of the flange 12 and the flange 16 lodged against the inner side of the wall of the band, the washer being adapted to bear on the face of the transmitter case and the flange to bear on the periphery of the case to hold the device in place on-the telephone. The mouth piece 5 has a contour adapted to permit the introduction therein of the speakers lips into the outer end of the same and bring the edge of the piece to bear on the face about the speaker's month. In the casing are apertured holes 17 which communicate with the chamber to admit air thereto when the talker breathes and to expel the air therefrom when talkmg.

To apply the device to the telephone, it is placed over the transmitter and its mouth piece and secured on the transmitter by the pressure of the screws 13 against the flange 16. The speaker closely adjusts the region of the face about the mouth to the edge of the mouth piece 5, thus leaving the lips free to move. The sound waves incident to articulate speech flow forward into the mouth piece of the transmitter. The sound waves outside of the transmitter strike the washer 14 and are measurably absorbed and deadened because of the resilient flexible nature of the washer. The variable pressures incident to rising and falling inflections of the voice are modified by the washer 14 and retarded by the limited area of communication between the bod 6 and the chamber 8. The opposed re ation of the openings 9 and the arrangement and disposition of the tangenital deflectors 10 causes the soundwaves to be deflected into the chamber 8, from the interior of the body 6 and to flow in a circle until quieted. The use of the device in connection with the telephone makes it possible to 'use the same in the office and any other environment without the use of sound proof telephone booths. talk being audible to persons in the vicinity. The device is sanitary and its parts are accessible with ease and dispatch for cleanmg.

Having described my invention what I claim is- 1. In a muffler device for telephones, the combination with the tele hone transmitter, of a cylindrical casing, a ollow cylindrical body within said casing and provided at its opposite ends with external annular flanges slidably bearing on the inner side of the wall of said casing and forming with the walls of the casing and the body an annular chamber about the body, a plurality of longitudinally extending apertures in the wall of said body and adapted to provide communication between the interior of the body and said chamber, a concentric band having its inner end slidably mounted on the inner end of said casing and its outer end mounted on the peripheral edge of the transmitter case, a flexible resilient washer of absorbent material mounted in the inner end of said band and adapted to encircle It also allows talking without the the neck of the'transmitter mouth piece, and atmouth piece combined with the outer end of said casing and horizontally aligned with the mouth piece on the transmitter when projected into said body.

2. In a mufller device for telephones, the combination with the telephone transmitter,

of a cylindrical casing, a hollow cylindrical body within said casing and provided at its opposite ends with external annular flanges slidably bearing on the inner side of the wall of said casing and forming with the walls of the casing and the body an annular chamber about the body, a plurality of longitudinally extending apertures in the wall of said body and adapted to provide communicationbetween the interior of the body and said chamber, a plurality of holes apertured in the wall of said casing and communicating with the chamber encircling said body, a concentric band having its inner end slidably mounted on the inner end of said casing and its outer end mounted on the transmitter case, a flexible resilient washer of absorbent material mounted in the inner end of said band and adapted to encircle the neck of the transmitter mouth piece, a rubber washer mounted in the outer end of said band and having a peripheral flange adapted to be interposed between the band and the transmitter case, and a month KARL J. NASH. 

